Effects of artificial light at night (ALAN) on the development and behaviors of zebrafish in early life stages.

内容摘要

Artificial light at night (ALAN), a form of physical pollution with growing global impacts, has been shown to induce various adverse effects on terrestrial organisms. However, studies on the effects of ALAN on aquatic organisms, particularly fish during early life stages, remain limited. In this study, zebrafish embryos were exposed to ALAN at 0, 25, 75, and 225 lx until 144 hours post-fertilization (hpf) with manipulated circadian cycles (light/dark or light/ALAN) to assess alterations in development, survival, behavior, and the monoaminergic system. The results showed that ALAN exerted no significant effects on the survival rate, hatching time, or blood flow velocity (at 72 hpf) of zebrafish embryos/larvae, but increased the embryonic heart rate (at 48 hpf) under the 75 and 225 lx conditions. Concurrently, the eye area of zebrafish exhibited a progressive reduction, accompanied by a decreased optokinetic response (OKR). Moreover, ALAN exposure decreased locomotor activity and induced marked anxiety-like behavior in zebrafish larvae. Biochemical analysis revealed significantly decreased levels of DA and its metabolites in zebrafish, which were associated with the observed physiological and behavioral deficits. In addition, the visual deficits induced by ALAN were closely linked to the behavioral alterations in zebrafish larvae. In summary, ALAN exposure is closely linked to the dopaminergic pathway, which correlates with disrupted early-life development and behavioral impairments in zebrafish. These findings highlight the potential risks that nocturnal light pollution poses to aquatic ecosystems, particularly in urbanized areas.